fix: semgrep-subprocess-shell-true

[ai-remediation]

Pull Request — Semgrep Rule Fix

• Rule ID: subprocess-shell-true
• Rule Message: Found 'subprocess' function 'Popen' with 'shell=True'. This is dangerous because this call will spawn the command using a shell process. Doing so propagates current shell settings and variables, which makes it much easier for a malicious actor to execute commands. Use 'shell=False' instead.
• File Path: unsloth/chat_templates.py
• Line: 2694